diff options
Diffstat (limited to 'src/third_party/gperftools-2.7/src/maybe_threads.cc')
| -rw-r--r-- | src/third_party/gperftools-2.7/src/maybe_threads.cc | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/src/third_party/gperftools-2.7/src/maybe_threads.cc b/src/third_party/gperftools-2.7/src/maybe_threads.cc new file mode 100644 index 00000000000..ef7e582c9de --- /dev/null +++ b/src/third_party/gperftools-2.7/src/maybe_threads.cc @@ -0,0 +1,177 @@ +// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- +// Copyright (c) 2005, Google Inc. +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +// --- +// Author: Paul Menage <opensource@google.com> +// +// Some wrappers for pthread functions so that we can be LD_PRELOADed +// against non-pthreads apps. +// +// This module will behave very strangely if some pthreads functions +// exist and others don't. + +#include "config.h" +#include <assert.h> +#include <string.h> // for memcmp +#include <stdio.h> // for __isthreaded on FreeBSD +// We don't actually need strings. But including this header seems to +// stop the compiler trying to short-circuit our pthreads existence +// tests and claiming that the address of a function is always +// non-zero. I have no idea why ... +#include <string> +#include "maybe_threads.h" +#include "base/basictypes.h" +#include "base/logging.h" + +// __THROW is defined in glibc systems. It means, counter-intuitively, +// "This function will never throw an exception." It's an optional +// optimization tool, but we may need to use it to match glibc prototypes. +#ifndef __THROW // I guess we're not on a glibc system +# define __THROW // __THROW is just an optimization, so ok to make it "" +#endif + +// These are the methods we're going to conditionally include. +extern "C" { + int pthread_key_create (pthread_key_t*, void (*)(void*)) + __THROW ATTRIBUTE_WEAK; + int pthread_key_delete (pthread_key_t) + __THROW ATTRIBUTE_WEAK; + void *pthread_getspecific(pthread_key_t) + __THROW ATTRIBUTE_WEAK; + int pthread_setspecific(pthread_key_t, const void*) + __THROW ATTRIBUTE_WEAK; + int pthread_once(pthread_once_t *, void (*)(void)) + ATTRIBUTE_WEAK; +#ifdef HAVE_FORK + int pthread_atfork(void (*__prepare) (void), + void (*__parent) (void), + void (*__child) (void)) + __THROW ATTRIBUTE_WEAK; +#endif +} + +#define MAX_PERTHREAD_VALS 16 +static void *perftools_pthread_specific_vals[MAX_PERTHREAD_VALS]; +static int next_key; + +// NOTE: it's similar to bitcast defined in basic_types.h with +// exception of ignoring sizes mismatch +template <typename T1, typename T2> +static T2 memcpy_cast(const T1 &input) { + T2 output; + size_t s = sizeof(input); + if (sizeof(output) < s) { + s = sizeof(output); + } + memcpy(&output, &input, s); + return output; +} + +int perftools_pthread_key_create(pthread_key_t *key, + void (*destr_function) (void *)) { + if (pthread_key_create) { + return pthread_key_create(key, destr_function); + } else { + assert(next_key < MAX_PERTHREAD_VALS); + *key = memcpy_cast<int, pthread_key_t>(next_key++); + return 0; + } +} + +int perftools_pthread_key_delete(pthread_key_t key) { + if (pthread_key_delete) { + return pthread_key_delete(key); + } else { + return 0; + } +} + +void *perftools_pthread_getspecific(pthread_key_t key) { + if (pthread_getspecific) { + return pthread_getspecific(key); + } else { + return perftools_pthread_specific_vals[memcpy_cast<pthread_key_t, int>(key)]; + } +} + +int perftools_pthread_setspecific(pthread_key_t key, void *val) { + if (pthread_setspecific) { + return pthread_setspecific(key, val); + } else { + perftools_pthread_specific_vals[memcpy_cast<pthread_key_t, int>(key)] = val; + return 0; + } +} + + +static pthread_once_t pthread_once_init = PTHREAD_ONCE_INIT; +int perftools_pthread_once(pthread_once_t *ctl, + void (*init_routine) (void)) { +#ifdef __FreeBSD__ + // On __FreeBSD__, calling pthread_once on a system that is not + // linked with -pthread is silently a noop. :-( Luckily, we have a + // workaround: FreeBSD exposes __isthreaded in <stdio.h>, which is + // set to 1 when the first thread is spawned. So on those systems, + // we can use our own separate pthreads-once mechanism, which is + // used until __isthreaded is 1 (which will never be true if the app + // is not linked with -pthread). + static bool pthread_once_ran_before_threads = false; + if (pthread_once_ran_before_threads) { + return 0; + } + if (!__isthreaded) { + init_routine(); + pthread_once_ran_before_threads = true; + return 0; + } +#endif + if (pthread_once) { + return pthread_once(ctl, init_routine); + } else { + if (memcmp(ctl, &pthread_once_init, sizeof(*ctl)) == 0) { + init_routine(); + ++*(char*)(ctl); // make it so it's no longer equal to init + } + return 0; + } +} + +#ifdef HAVE_FORK + +void perftools_pthread_atfork(void (*before)(), + void (*parent_after)(), + void (*child_after)()) { + if (pthread_atfork) { + int rv = pthread_atfork(before, parent_after, child_after); + CHECK(rv == 0); + } +} + +#endif |